keyboard-diy VS keyboards

No IO expander needed. My board is 5x6 each side so 11 wires are routed from one side to the other to make a combined matrix of 5x12. I counted 14 wires in USB-C, allowing larger boards like 7x7 or 6x8. It's all hand-wired and the build log is at https://github.com/macroxue/keyboard-diy

Also, have you checked ergodox? Dactyl? https://github.com/topics/ergonomic-keyboard looks like what you search for, random link was sending me to page https://github.com/macroxue/keyboard-diy

In a previous post https://www.reddit.com/r/ErgoMechKeyboards/comments/qsr8mg/minimalist_highangle_tenting/, I had only a bridge piece connecting the two split boards. The structure sits on the table but it can't be lifted up as the two splits will just slip out. In this post, the three additional pieces, especially the white bar in the middle, push the two splits outwards. The tension prevents the splits from slipping out when the board is lifted. Please see https://github.com/macroxue/keyboard-diy for the build log and 3D-printed models.

I've built split keyboards with one Teensy controller and one USB-C cable connecting the two splits. Please see https://github.com/macroxue/keyboard-diy for the build log. It might give you a few ideas.

If you want the ortholinear layout, maybe the Darknight: https://github.com/macroxue/keyboard-diy

RedBaron: a tented split by u/macroxue with documentation & STL files.

My own design; https://github.com/tzarc/djinn

You can see an example of this with the Djinn Rev 2a

I have found one with no wireless module (djinn) but i really want a wireless one.

djinn

https://i.imgur.com/Z4FZ0t1.jpg Finally reflect I'm done with the hardware. This was my first non-kit board where I had to order all the components myself. Soldering was tough. Blood, sweat and ⠀tears were shed, but I think it was worth it. Big thanks to u/tzarc for the great piece of kit and for all folks on the djinn discord channel for putting up with all my noob questions! All the required info is here: https://github.com/tzarc/djinn Now I just have to learn to type better 😂 Here are some progress pics https://imgur.com/a/5h1qPb1

There may be enthusiast mechanical keyboards that use faster ports. My keyboard uses an Elite-C MCU in each half. I've heard some more modern stuff is switching to ARM for the MCUs.

Here's a keyboard that uses an ARM MCU:

https://github.com/tzarc/djinn

Most of the open source designs do not have protection on the TRRS connector. There are many kinds of protection that can be built such as for ESD (static electricity), over voltage, over current (short circuit), noise (interference), etc. All of these require components and board real estate. You can check out the Djinn Djinn keyboard It implements protection on the TRRS port and it is a BEAST. The Pro Micro form factor for MCU boards is pretty small so there is limited space for this kind of circuitry. However, if a keyboard has an onboard controller (no separate microcontroller) it might have some protection, at least on the USB connector.

You can. I learned from this guy: https://github.com/tzarc/djinn. I just don’t remember how (I haven’t used kicad in a while). You might be able to figure it out by looking at the footprints he used here. Even the MCU footprint is a reversible one with all the traces included iirc.